Here is the abstract you requested from the rf_2008 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.

During RF power transistor ceramic packaging manufacture, differing thermal expansion coefficients between brazed components results in permanent deflection (i.e. camber). Under torque down CW (continuous wave) device operation, this deflection contributes to a spatially varying increased thermal contact resistance between the package heat spreader and its high conductivity test fixture base. Typically, the interstitial material is a thermal grease enabling removal of package in a convenient manner. The following technical brief attempts to place theoretical limits on this conforming surface contact resistance contribution using well-established thermal and mechanical analysis techniques. Microthermal IR imaging of steady state test die operation will also be correlated to the analysis.